A joint female hockey team formed by the two nations will march together under a unification flag at the Winter Olympics' opening ceremony. Chung Sung-Jun/Getty Images

Six months ago, it seemed incomprehensible that the bitterly divided regimes of North and South Korea could find a way to form a joint team to march under the same flag at next month’s Winter Olympics. At that time, it seemed more likely that the countries would find themselves involved in another round of hostilities with all the potential to plunge the region into all-out war.

And yet, in what is being hailed as a major step towards easing tensions between the two embattled regimes, it has now been announced that a joint female hockey team formed by the two nations will march together under a unification flag - a pale blue silhouette of the whole Korean peninsula - at the Games’ opening ceremony in the mountainous county of Pyeongchang next month.

This unprecedented display of Korean unity, moreover, is all the more symbolic for the fact it is taking place just 50 miles south of the Demilitarised Zone (DMZ) that separates the communist North from the democratic South.

With South Korea offering to reciprocate by sending teams of its skiers to the North for joint training, there are hopes that this modest initiative between Pyongyang and Seoul could result in a more stable understanding being reached between the two countries.

Small steps they may be, but the rapprochement between North and South is a far cry from last year, when tensions between the two countries, as well as the entire region, were threatening a far more disastrous outcome. North Korean dictator Kim Jong-un’s insistence on continuing to test-fire ballistic missiles as part of his regime’s attempts to develop its nuclear weapons programme had prompted the worst crisis on the Korean peninsula since the brutal civil war of the 1950s. Millions of South Koreans were obliged to take to nuclear shelters as Seoul genuinely feared that Pyongyang would follow-up on its threat to obliterate its southern neighbour in a wave of missile strikes.

Nor were the fears engendered by Mr Kim’s bellicose stand confined to the immediate vicinity of North Korea. American intelligence experts believe the new generation of ballistic missiles being developed by North Korea will provide Pyongyang with the ability to fire nuclear-armed weapons at the American mainland, while many of the missile tests were conducted close to the territorial waters of Japan, one of Washington’s closest allies. Only last summer, Mr Kim’s reckless pursuit of developing North Korea’s nuclear weapons arsenal in the face of stiff international opposition was on the brink of causing a major regional conflagration.

That the world was not plunged into yet another unwelcome conflict, and female hockey players from North and South Korea will find themselves in the unconventional role of marching under the same flag next month, is in no small measure due to the tough stance US president Donald Trump has taken on the issue.

For more than two decades successive American administrations have tried and failed to bring Pyongyang to its senses. Washington’s approach, which dates back to the Clinton administration and continued through the Bush and Obama presidencies, has been a combination of carrot and stick – aid relief for North Korea in return for a freeze on its nuclear programme, with the imposition of stiff economic sanctions if Pyongyang failed to comply.

Despite the heroic efforts of a generation of American diplomats, this approach basically failed to achieve its goals because the threat to punish North Korea for non-compliance was fatally undermined by China’s continued support for its neighbour and ally. The North Korean economy relies almost entirely on Chinese support for its survival and China’s disinclination to harm a fellow communist regime frustrated American efforts to bring Pyongyang to its senses.

Mr Trump’s arrival at the White House, though, has seen a dramatic change in Washington’s approach, one that is now starting to pay dividends in terms of tangible changes in North Korea’s conduct. Mr Trump’s decision – which had the full backing of his national security team – to dispatch a powerful aircraft carrier battle group to the region when Mr Kim, or “rocket man” as the American president condescendingly calls him, continued test-firing his missiles had the desired effect of persuading the North Koreans, as well as their Chinese backers, that this time Washington was serious about resolving this issue once and for all.

In particular, Mr Trump’s no-nonsense approach, together with the alarming rhetoric that has at times characterised his attitude towards North Korea, appears to have had a salutary effect on Beijing, the only country with the ability to bring its influence to bear on Pyongyang. Fearing that the president’s actions might precipitate a major escalation in hostilities on its doorstep, the Chinese appear to have brought a degree of influence to bear on Mr Kim, thereby helping to defuse tensions.

It is, of course, far to early to say whether the presence of a joint team of female hockey players at next month’s Winter Olympics will have a lasting impact on relations between the two Korean states. The decades of hostility between the two governments is so deep-rooted that it could take a very long time before anything approaching a normalisation in relations can be achieved. But the fact that the two sides, given where they were only a few months ago, are now openly cooperating with each other represents a major transformation in the dynamics of the relationship between the two countries, one for which Mr Trump deserves some credit for helping to achieve.